The long-term objectives of this study are to continue to establish the developmental prognosis into adulthood of individuals with sex chromosome abnormalities (SCA) identified at birth in an unselected fashion between 1964 and 1974. In the course of this longitudinal study, we have documented the physical, endocrine, developmental, and psychological phenotypes of SCA children. The presence of language, learning, and neuromotor impairment in SCA children and of psychosocial dysfunction in SCA adolescents suggests that SCA adults are at risk for difficulty in social and vocational adaptation and may experience increased incidence of psychopathology. No studies of an unselected SCA adult cohort are in existence, and the absence of any newborn sex chromosome screening programs in the past two decades indicates that the Denver Study will be the first and possibly last foreseeable opportunity to study adult adaptation in this population. This proposal includes investigations of physical, endocrine, neurocognitive, vocational, and psychosocial characteristics of 42 SCA propositi and a control group that includes 32 siblings. The specific aims allow us to address questions raised in our earlier studies of this group and to complete the phenotypic profile from birth into adulthood of the 45,X, 47,XXX, 47,XXY, and sex chromosome mosaic karyotypes.